[astroCS] Nova jasna kometa C/2004 F4 (Bradfield)

[Marek Husarik]

Skoda, ze je nizko nad obzorom (Cetus) a zapada tesne po zapade Slnka. No
zhruba od 16. do 25. aprila t.r. by mala byt v zabere SOHO LASCO C3.

                       
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                          IAUC 8319
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COMET C/2004 F4 (BRADFIELD)
     On Mar. 28, A. C. Beresford, Myrtle Bank, South Australia,
reported the visual discovery of a possible new comet close to the
horizon in twilight by William A. Bradfield, during his search for
sungrazing comets, from observations made with a 0.25-m reflector
on Mar. 23.43 and 24.42 UT; further attempts to observe it had
failed until the last few days.  The delay in reporting was due to
difficulties in matching the sketch of observations with star
charts.  Below are additional observations that have been reported
following requests to several observers.

  2004 UT            R.A. (2000) Decl.       Mag.    Observer
  Mar. 23.43      1 50.0      - 1 26          8      Bradfield
       24.42      1 51.0      - 1 25                   "
  Apr.  8.4       2 08.5      - 1 36                   "
        9.368     2 09.1      - 1 24          5      McNaught
       11.3461    2 08 32.74  - 0 56 37.8     4      Lovejoy
       12.3427    2 07 39.50  - 0 30 59.2     3.3      "

W. A. Bradfield (Yankalilla, S.A.).  Original positions given for
  equinox 1950.0.  Magnitude guessed.
R. H. McNaught and T. M. Smith (Siding Spring Observatory).
  Strongly condensed blue coma with diameter about 0'.5; hint of a
  tail pointing up from the horizon.  Comet low in evening
  twilight; 20x120 binoculars.  Positional uncertainty stated as
  +/- 5'.  In-focus magnitude comparable to two nearby stars of mag
  5.6.  Also observed visually on Apr. 12.358, again almost stellar,
  blue, and with a short (perhaps 2'-long?) tail pointing up to the
 left at 10 degrees from vertical.
T. Lovejoy (Thornlands, Qld., Australia).  Long. = 153.267 deg, Lat.
  = -27.55 deg, h = 30 m.  On Apr. 11, nineteen co-added CCD images
  with Canon 300D camera + 100-mm f/4 camera lens; fairly obvious
 tail 0.5 deg long.

     The following very preliminary parabolic orbital elements are
from the above observations.

     T = 2004 Apr. 17.12 TT           Peri. = 332.49
                                      Node  = 222.66    2000.0
     q = 0.1690 AU                    Incl. =  63.21

                      (C) Copyright 2004 CBAT
2004 April 12                  (8319)            Daniel W. E. Green



                       
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                          IAUC 8319
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COMET C/2004 F4 (BRADFIELD)
     Ephemeris from orbital elements on IAUC 8319 (H = 8.0, n = 3):

2004 TT     R. A. (2000) Decl.   Delta     r    Elong. Phase    Mag.
Apr.  5     2 05.53   - 1 44.5   1.288   0.469   18.8   43.4    6.1
      7     2 07.42   - 1 40.8   1.227   0.412   17.9   48.3    5.6
      9     2 08.68   - 1 29.6   1.159   0.353   16.9   55.4    4.9
     11     2 08.75   - 1 03.7   1.085   0.294   15.5   66.0    4.2
     13     2 06.59   - 0 07.6   1.005   0.238   13.6   82.6    3.3
     15     2 00.31   + 1 51.7   0.923   0.191   10.3  109.6    2.4
     17     1 48.03   + 5 43.1   0.856   0.169    5.1  148.4    1.9
     19     1 32.28   +11 17.5   0.830   0.186    4.0  157.8    2.1
     21     1 18.89   +16 57.2   0.845   0.231   10.3  128.6    2.9
     23     1 09.74   +21 44.3   0.882   0.287   15.8  107.3    3.7
     25     1 04.02   +25 36.7   0.929   0.346   20.1   92.6    4.4
     27     1 00.66   +28 46.2   0.980   0.404   23.4   82.0    5.0
     29     0 58.90   +31 23.7   1.031   0.462   26.2   74.1    5.6
May   1     0 58.23   +33 37.4   1.081   0.518   28.5   67.9    6.0
      3     0 58.32   +35 33.3   1.130   0.573   30.4   63.0    6.5
      5     0 58.93   +37 15.3   1.177   0.626   32.1   58.9    6.8